docs: def find(self, name):
          """Find a vgroup given its name, returning its reference
          number if found.
  
          Args::
  
            name     name of the vgroup to find
  
          Returns::
  
            vgroup reference number
  
          An exception is raised if the vgroup is not found.
  
          C library equivalent: Vfind
                                                    """
  
          refnum = _C.Vfind(self._hdf_inst._id, name)
          if not refnum:
              raise HDF4Error("vgroup not found")
          return refnum